At the present time and through all recorded history, a bed of one form or another has been the place where human couples have had sexual intercourse. It requires that both individuals support their own weight and often bear the weight of their partner, requiring great expenditure of energy as well as the use of the hands and considerable body control, just to gain advantageous access to one another.
Beds are disadvantageous and restricting due to difficulties in achieving and maintaining a favorable position for a sustained period. Sexual intimacy on a conventional bed requires a great expenditure of energy due to the bed's limitations. Persons of decreased or diminished physical ability may not be able to function well or at all in a bed. Generally, beds restrict access to one another due to the mechanical difficulties a two dimensional mattress surface presents the couple.
The desire or need for intimacy remains a strong impulse for couples but the energy, strength and balance requirements may limit or destroy a couple's chance for intimacy. Those who are aged, infirm, handicapped, such as through loss of a limb, for example, or otherwise physically unable to engage in sexual intercourse with their partner to the extent desired present a real need that has not been fulfilled in the past.